Duplicating machines



Feb. 26, 1957 E. A. TOMLIN DUPLICATING MACHINES Filed 001:. 8,v 1953 3Sheets-Sheet l 1 r/vL/twiae 50/4/1120 ALBBPrTM Feb. 26', 1957 E. A.TOMLIN DUPLICATING MACHINES 3 Shets-Sheet 2 Filed Oct. 8, 1953 Feb. 26,1957 I E. A. TOMLIN ,783,043

- DUPLICATING MACHINES Filed Oct. 8, 1953 3 Sheets-Sheet 3 III I Im/a/s/vro e m/9'0 flzaaer 7a/am BY United States Patent DUPLICATINGMACHINES Edward Albert Tomlin, Southgate, England, assignor to GestetnerLimited, London, England, a British com- Application October 8, 1953,Serial No. 384,981

Claims priority, application Great Britain August 4, 1953 2Claims. (Cl.271-63) This invention concerns duplicating machines, more particularlymachines in which a stencil travels around a top and bottom cylinder andthe sheets of paper are fed in succession between the bottom cylinderand a pressure roller which presses the sheets against the travellingstencil, the sheets being delivered from between the bottom cylinder andthe pressure roller to a tray or platform to build up a stack of copiesthereon.

It is found more especially with very thin paper, that the copies beingdelivered to the stack are pushed across the inked face of the topmostcopy and consequently that the copies become smudged, and thisdisability becomes more pronounced as the rate of feed through themachine is increased.

It is known, in order to overcome this disability, to bow the sheets asthey are delivered from the machine about an axis extending in thegeneral direction of delivery with a concave face downwardly directed sothat a certain rigidity is imparted to the sheets with the result thatthe copies are carried over the topmost copy of a stack and the presentinvention is concerned with an improved arrangement whereby such bowingmay be effected.

Broadly the object of the present invention is to provide a stencilduplicating machine which incorporates an attachment for bowing sheetsas they are delivered, said attachment being readily removable from themachine for ease of maintenance and repair.

A practical application of the present invention will now be described,by way of example only, with reference to the accompanying drawings ofwhich:

Figure 1 is a diagrammatic side view of a duplicating machine inaccordance with the present invention.

Figure 2 is a view similar to Figure 1 showing a part of the machine toa larger size and with a cover plate removed to show certain of thedetails of the machine,

Figure 3 is a view, partly in section, in the direction of the arrow'3of Figure 2,

Figure 4 is a side view showing a detail of construction of themechanism of Figure 2, and to a larger size, and

Figure 5 is a view similar to Figure 4 and showing the mechanism inanother operative position.

Referring to Figure l, the machine comprises a frame 5 supported on abase 6, a platform 7 upon which a stack 8 of paper is placed to be fedthrough the machine, a delivery platform 9 upon which the stack 10 ofcopies is built on delivery of the copies from the machine, a topcylinder 11, a bottom cylinder 12, a pressure roller 13 and means,generally indicated at 14, which passes around cylinders 11, 12 and towhich there is secured a silk screen and a stencil for movement aroundthe cylinders in any well known manner. The copies are delivered fromthe machine on to the stack 10 against a stop 15 carried by the platform9. The machine is driven by a handle 16 mounted on a shaft 17 whichcarries a spur gear 18 meshing with a pinion 49 supported on the shaftof the bottom cylinder 12.

The sheets of paper are fed into the machine in conventional manner tobetween the bottom cylinder 12 and 2,783,043 Patented Feb. 26, 1957 icethe pressure roller 13. The latter is supported upon a bar 19 which isoscillated by a mechanism (not shown but of conventional construction)whereby the roller 13 is moved towards and away from the bottom cylinder12. The silk screen and stencil referred to are secured to the means 14by bars and plates which project beyond the outer face of the stenciland the roller 13 is oscillated to clear such projections. When a sheetof paper from the stack 8 is fed on to the stencil the roller 13 isbrought into engagement with the paper to press it against the stencil.The

mechanism for oscillating the roller 13 does not form part of thepresent invention and is therefore not described in detail.

A member, generally indicated by the reference numeral 20, is hooked at2001 over the bar 19 and comprises a spring clip 21 to engage a spindle22 by which the mem- There is provided a stripper mechanism to ensurethat the copies, which have a tendency to stick to the stencil,disengage the stencil immediately after they are delivered from betweenthe cylinder 12 and the roller 13. The stripper mechanism comprises abar 25 (Figure 3) supported in bearings 26, 27 carried by the frames 5of the machine, and a pair of stripper blades 28 supported from the bar25. The blades have inclined ends, as at 50 (Figure 2) theends beingadapted to approach the-cylinder 12 at a tangent. As more clearly shownin Figure 3, the

blades 28' are mounted on blocks 29 which carry knurled nuts 30 forsecuring the blocks against movement to the bar 25. When the knurlednuts are released the blocks, andv the stripper blades 28, are capableof adjustment lengthwise of the bar, i. e. lengthwise of the cylinder 12and across the width of the sheet of paper. One end. of the bar 25carries a lever 31 having a pin 32 (Figure 2) which enters a slot 33 ina rocking member 34 which is pivotally supported at 35. As the memberrocks, the engagement of the pin 32 and the slot 33 results in the bar25 being oscillated so that the stripper blades 28 are adjusted from thefull line position to the chain-dotted position shown in Figure 2. A cam36 is mounted on shaft 17 and is engaged by a cam follower 37 carried bylever 38, the follower being held in engagement with the cam by a spring39. The cam imparts a rocking movement to the member 34.

The bearing 26 comprises a casing 40, a plunger 41 within the casing anda spring 42 urging the plunger 41 towards the left as seen in Figure 3.The end of the easing 40 has a hole to receive the rounded part 43 ofthe bar 25. When the bar 25 is forced to the right to com press thespring 42 the bar can disengage the bearing 27 and be taken out from themachine.

In use: a sheet of paper as it is delivered from between the cylinder 12and the roller 13 is engaged on its upper surface and at its forwardedge by the blades 28 which strip the copy from the stencil, the copybeing forced to travel beneath the stripper blades-which thereforeengage the upper surface of the copy towards the marginal edges thereofas shown in Figure 3. After the leading edge of the copy is strippedfrom the stencil, it engages the guides 23 and is carried up and overthe tops 24 thereof. The guides 23 engage the under surface of the paperbetween the blades 28 and it will be seen from Figure 3 that the of thesheet, the concave surface being downwardly directed. As a consequenceof the bowing there is imparted to the sheet a certain rigidity whichensures that it is carried above the stack until the leading edge of thesheet strikes the stop whereupon the copy descends on to the stack andthere is therefore no risk of the ink on the topmost copy of the stackbeing smudged upon the delivery of the next succeeding copy. The bowedsheet is shown at x in Figure 3.

The purpose of oscillating the blades 28 is to ensure that, as also isrequired in the case of the pressure roller 13, they clear theprojections of the means 14 which secure the silk screen and stencil tothe cylinders 11 and 12.

The blades 28 are required closely to approach the stencil but not toengage therewith and in Figures 4 and 5 there is shown means foradjusting the extent of oscilla tion of the blades towards the lowercylinder 12 for this purpose. An outer face cam 55 pivotally carried, at56, on member 34 and lockable against movement by screw 57 engages pin32. Figure 4 shows cam 55 in its fully raised position and with thelowest part of its cam face engaged by pin 32 so that the pin may enterfully into the slot in member 34 whereby blades 28 are raised to theirgreatest extent--as shown. In Figure 5 cam 55 has been adjusted so thatthe highest part of its cam face will be engaged by pin 32 which isconsequently prevented from fully entering the slot of member 34 withthe result that the blades 28 are held otf to some extent from cylinder12 as shown in Figure 5.

As the blades 28 may be swung away from the stenoil, the cam follower 37being thereby moved away from cam 36 against the action of spring 39, ifa sheet of paper is inadvertently brought between the blades and thestencil, or if an obstruction is encountered by the blades whenoscillating them towards the stencil, it is ensured that the bladesresiliently ride over the sheet of paper or the obstruction.

I claim:

1. In a stencil duplicating machine comprising a pair of side frames,two vertically spaced-apart members extending across between the frames,a pair of rollers supported by, and extending between, the side frames,sheets of paper being fed in succession between the rollers forduplication of the copies, and a pair of blades to engage the sidemargins of the sheets and strip the copies from the stencil, theprovision of a device comprising an upwardly inclined guide to engagebeneath, and raise, the central region of the sheets relatively to thestripper blades as the sheets are stripped from the stencil, a hookbelow the guide for attaching the device to the upper of said verticallyspaced-apart members and a spring catch below said hook to engage thelower of said vertically spaced-apart members said hook and catchsecuring said device to the machine in a readily removable manner, saidvertically spaced-apart members being so disposed with respect to thesaid rollers and stripper blades that the said device hows the sheets inthe direction of travel of the copies during delivery from the rollers.

2. In a stencil duplicating machine comprisng a pair of side frames, twovertically spaced-apart members extending across between the frames, apair of rollers sup ported by, and extending between, the side frames,sheets of paper being fed in succession between the rollers forduplication of the copies and a pair of blades to engage the sidemargins of the sheets and strip the copies from the stencil, theprovision of a device comprising an upright, plate-like part, a pair ofupwardly inclined guides carried by the plate-like part, said guidesbeing spaced apart axially of the rollers and presenting their concavesurface to the stencil, a hook beneath each guide to rest on the upperof said vertically spaced-apart members and a spring catch carriedtowards the bottom of the plate-like part to clip over the lower of saidvertically spaced-apart members and prevent disengagement of the hook,said vertically spaced-apart members being so disposed with respect tothe said rollers and stripper blades that the said device bows thesheets in the direction of travel of the copies during delivery from therollers.

References Cited in the file of this patent UNITED STATES PATENTS832,217 Smith Oct. 21, 1906 1,140,883 Dick May 25, 1916 1,174,414Hastings Mar, 7, 1916 1,928,223 Harding Sept. 26, 1933 1,933,712 CreedNov. 7, 1933

